Taking children to the opera: it can work beautifully, depending . . .

It's nice to know there's a place for children in the high-culture world of opera. Even the lofty Metropolitan Opera had its annual presentation of ''Hansel and Gretel,'' the blithe, tuneful - not to mention enduring - romp by Engelbert Humperdinck. I paid a visit on New Year's Day with my family, wondering what chemistry might arise between 11-year-old kids and a 90-year-old opera.

The chemistry was good, due both to Humperdinck's artistry and the Met's energetic approach. The production moved along nicely, without speeding, and the settings by Robert O'Hearn proved as timeless as they are lavish. Even some of the special effects - particularly an exploding oven - passed the hard test of pleasing youngsters accustomed to ''Star Wars'' and Pac-Man.

After the final curtain fell, I asked the children which voices they preferred. Not surprisingly, they chose Michael Devlin's hearty performance as the father over the sweet yet wan Gretel of Judith Blegen, though it's hard to say why they weren't impressed with Frederica von Stade's nicely boyish Hansel. I don't think they were paying much attention to musical qualities during Sheila Nadler's hammy turn as the Witch, but its cackling high spirits made a big hit.

The Met has no monopoly on music for young folks at Lincoln Center, though. The Little Orchestra Society has been around for 34 years, and for the past three it has presented a series of ''Happy Concerts for Young People.''

That title is cloying. But the music is solid, judging from my visit to the group's modestly mounted yet delightfully performed production of ''Amahl and the Night Visitors,'' staged for the second year in a row by composer Gian Carlo Menotti himself - who was on hand to welcome the audience and make a few engaging remarks before turning the spotlight to conductor Dino Anagnost and company.

My youngsters responded to the production with audible enthusiasm - especially when the stage of Avery Fisher Hall suddenly swarmed with Amahl's animals, making a cuddly personal appearance.

The society figures that some 25,000 people will attend its current season (with two performances of each program) in addition to 10,000 disadvantaged children who will be welcomed at concerts and dress rehearsals. That's a lot of music for a lot of youngsters. A hearty round of applause has been well earned by this enterprising institution.

Their new season continues Jan. 15 with ''Toy Symphonies,'' featuring Respighi's ballet ''La Boutique Fantasque'' with artist Lisl Weil drawing larger-than-life murals as accompaniment. A program called ''What Is an Orchestra?'' will be given Feb. 15, highlighted by Benjamin Britten's fine ''Young Person's Guide to the Orchestra'' with its forceful echoes of Purcell. Program 4, on March 12, is ''Music and Magic,'' with prestidigitation to the tune of Dukas's ''The Sorcerer's Apprentice.''

The series will end April 9 with a Dance Roundup featuring excerpts from Aaron Copland's ''Billy the Kid'' and ''Rodeo.''